platform/chrome: cros_ec_vbc: Fix -Warray-bounds warnings

GCC-13 (and Clang) does not like having a partially allocated object,
since it cannot reason about it for bounds checking.

Notice that the compiler is legitimately complaining about accessing
an object (params, in this case) for which not enough memory was
allocated.

The object is of size 20 bytes:

struct ec_params_vbnvcontext {
uint32_t op; /* 0 4 */
uint8_t block[16]; /* 4 16 */

/* size: 20, cachelines: 1, members: 2 */
/* last cacheline: 20 bytes */
};

but only 16 bytes are allocated:

sizeof(struct ec_response_vbnvcontext) == 16

In this case, as only enough space for the op field is allocated,
we can use an object of type uint32_t instead of a whole
struct ec_params_vbnvcontext (for which not enough memory is
allocated).

Fix the following warning seen under GCC 13:
drivers/platform/chrome/cros_ec_vbc.c: In function ‘vboot_context_read’:
drivers/platform/chrome/cros_ec_vbc.c:36:15: warning: array subscript ‘struct ec_params_vbnvcontext[1]’ is partly outside array bounds of ‘unsigned char[36]’ [-Warray-bounds=]
36 | params->op = EC_VBNV_CONTEXT_OP_READ;
| ^~
In file included from drivers/platform/chrome/cros_ec_vbc.c:12:
In function ‘kmalloc’,
inlined from ‘vboot_context_read’ at drivers/platform/chrome/cros_ec_vbc.c:30:8:
./include/linux/slab.h:580:24: note: at offset 20 into object of size 36 allocated by ‘kmalloc_trace’
580 | return kmalloc_trace(
| ^~~~~~~~~~~~~~
581 | kmalloc_caches[kmalloc_type(flags)][index],
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
582 | flags, size);
| ~~~~~~~~~~~~

Link: https://github.com/KSPP/linux/issues/278
Signed-off-by: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/ZCTrutoN+9TiJM8u@work
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>

platform/chrome: cros_ec_vbc: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230927081040.2198742-7-u.kleine-koenig@pengutronix.de
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>

platform/chrome: Constify static attribute_group structs

The only usage of these is to print their name in a dev_err-message, and
to pass their address to sysfs_create_group() and sysfs_remove_group(),
both which takes pointers to const. Make them const to allow the compiler
to put them in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Link: https://lore.kernel.org/r/20210109001748.58036-1-rikard.falkeborn@gmail.com

platform/chrome: Use kobj_to_dev() instead of container_of()

Use kobj_to_dev() instead of container_of().

Signed-off-by: Wang Qing <wangqing@vivo.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

platform/chrome: cros_ec_vbc: Use cros_ec_cmd_xfer_status helper

This patch makes use of cros_ec_cmd_xfer_status() instead of
cros_ec_cmd_xfer(). In this case the change is trivial and the only
reason to do it is because we want to make cros_ec_cmd_xfer() a private
function for the EC protocol and let people only use the
cros_ec_cmd_xfer_status() to return Linux standard error codes.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: Prashant Malani <pmalani@chromium.org>

cros_ec: treewide: Remove 'include/linux/mfd/cros_ec.h'

This header file now only includes the cros_ec_dev struct, however, is the
'include/linux/platform_data/cros_ec_proto.h' who contains the definition of
all the Chrome OS EC related structs. There is no reason to have a
separate include for this struct so move to the place where other
structs are defined. That way, we can remove the include itself, but also
simplify the common pattern

#include <linux/mfd/cros_ec.h>
#include <linux/platform_data/cros_ec_proto.h>

for a single include

#include <linux/platform_data/cros_ec_proto.h>

The changes to remove the cros_ec.h include were generated with the
following shell script:

git grep -l "<linux/mfd/cros_ec.h>" | xargs sed -i '/<linux\/mfd\/cros_ec.h>/d'

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Sebastian Reichel <sre@kernel.org>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

mfd / platform: cros_ec: Reorganize platform and mfd includes

There is a bit of mess between cros-ec mfd includes and platform
includes. For example, we have a linux/mfd/cros_ec.h include that
exports the interface implemented in platform/chrome/cros_ec_proto.c. Or
we have a linux/mfd/cros_ec_commands.h file that is non related to the
multifunction device (in the sense that is not exporting any function of
the mfd device). This causes crossed includes between mfd and
platform/chrome subsystems and makes the code difficult to read, apart
from creating 'curious' situations where a platform/chrome driver includes
a linux/mfd/cros_ec.h file just to get the exported functions that are
implemented in another platform/chrome driver.

In order to have a better separation on what the cros-ec multifunction
driver does and what the cros-ec core provides move and rework the
affected includes doing:

- Move cros_ec_commands.h to include/linux/platform_data/cros_ec_commands.h
- Get rid of the parts that are implemented in the platform/chrome/cros_ec_proto.c
driver from include/linux/mfd/cros_ec.h to a new file
include/linux/platform_data/cros_ec_proto.h
- Update all the drivers with the new includes, so
- Drivers that only need to know about the protocol include
- linux/platform_data/cros_ec_proto.h
- linux/platform_data/cros_ec_commands.h
- Drivers that need to know about the cros-ec mfd device also include
- linux/mfd/cros_ec.h

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Series changes: 3
- Fix dereferencing pointer to incomplete type 'struct cros_ec_dev' (lkp)
Signed-off-by: Lee Jones <lee.jones@linaro.org>

platform/chrome: cros_ec: Make some symbols static

Fix sparse warning:

drivers/platform/chrome/cros_ec_debugfs.c:256:30: warning: symbol 'cros_ec_console_log_fops' was not declared. Should it be static?
drivers/platform/chrome/cros_ec_debugfs.c:265:30: warning: symbol 'cros_ec_pdinfo_fops' was not declared. Should it be static?
drivers/platform/chrome/cros_ec_lightbar.c:550:24: warning: symbol 'cros_ec_lightbar_attr_group' was not declared. Should it be static?
drivers/platform/chrome/cros_ec_sysfs.c:338:24: warning: symbol 'cros_ec_attr_group' was not declared. Should it be static?
drivers/platform/chrome/cros_ec_vbc.c:104:24: warning: symbol 'cros_ec_vbc_attr_group' was not declared. Should it be static?
drivers/platform/chrome/cros_ec_lpc.c:408:25: warning: symbol 'cros_ec_lpc_pm_ops' was not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

platform/chrome: cros_ec_vbc: switch to SPDX identifier

Adopt the SPDX license identifier headers to ease license compliance
management.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>

mfd / platform: cros_ec_vbc: Instantiate only if the EC has a VBC NVRAM

The cros-ec-vbc driver is DT-only and there is a DT property that
indicates if the EC has the VCB NVRAM, in such case instantiate the
driver but don't instantiate on the other cases.

To do this move the check code to its parent instead of play with the
attribute group visibility. This changes a bit the actual behaviour.
Before the patch if an EC doesn't have a VBC NVRAM an empty vbc folder
is created in /sys/class/chromeos/<ec-device-name>, after the patch the
empty folder is not created, so, the folder is only created if the vbc
is set.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

mfd / platform: cros_ec: Move vbc attributes to its own driver

The entire way how cros sysfs attibutes are created is broken.
cros_ec_vbc should be its own driver and its attributes should be
associated with a vbc driver not the mfd driver. In order to retain
the path, the vbc attributes are attached to the cros_class.

The patch also adds the sysfs documentation.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

platform/chrome: Use to_cros_ec_dev more broadly

Move to_cros_ec_dev macro to cros_ec.h and use it when the private ec
object is needed from device object.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Benson Leung <bleung@chromium.org>

cros_ec: Split cros_ec_devs module

This patch splits the cros_ec_devs module in two parts with a
cros_ec_dev module responsible for handling MFD devices registration and
a cros_ec_ctl module responsible for handling the various user-space
interfaces.

For consistency purpose, the driver name for the cros_ec_dev module is
now cros-ec-dev instead of cros-ec-ctl.

In the next commit, the new cros_ec_dev module will be moved to the MFD
subtree so mfd_add_devices() calls are not done from outside MFD.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

platform/chrome: Support reading/writing the vboot context

Some EC implementations include a small nvram space used to store
verified boot context data. This patch offers a way to expose this
data to userspace.

Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Emilio López <emilio.lopez@collabora.co.uk>
Signed-off-by: Olof Johansson <olof@lixom.net>